title: Reversing bone loss by directing mesenchymal stem cells to bone.
abstract: Bone regeneration by systemic transplantation of mesenchymal stem cells (MSCs) is problematic due to the inability to control the MSCs' commitment, growth, and differentiation into functional osteoblasts on the bone surface. Our research group has developed a method to direct the MSCs to the bone surface by conjugating a synthetic peptidomimetic ligand (LLP2A) that has high affinity for activated α4β1 integrin on the MSC surface, with a bisphosphonates (alendronate) that has high affinity for bone (LLP2A-Ale), to direct the transplanted MSCs to bone. Our in vitro experiments demonstrated that mobilization of LLP2A-Ale to hydroxyapatite accelerated MSC migration that was associated with an increase in the phosphorylation of Akt kinase and osteoblastogenesis. LLP2A-Ale increased the homing of the transplanted MSCs to bone as well as the osteoblast surface, significantly increased the rate of bone formation and restored both trabecular and cortical bone loss induced by estrogen deficiency or advanced age in mice. These results support LLP2A-Ale as a novel therapeutic option to direct the transplanted MSCs to bone for the treatment of established bone loss related to hormone deficiency and aging.
authors.affiliation: Department of Internal Medicine, University of California at Davis Medical Center, Sacramento, California, USA.
authors.forename: Wei
authors.initials: W
authors.lastname: Yao
authors.forename: Min
authors.initials: M
authors.lastname: Guan
authors.forename: Junjing
authors.initials: J
authors.lastname: Jia
authors.forename: Weiwei
authors.initials: W
authors.lastname: Dai
authors.forename: Yu-An E
authors.initials: YA
authors.lastname: Lay
authors.forename: Sarah
authors.initials: S
authors.lastname: Amugongo
authors.forename: Ruiwu
authors.initials: R
authors.lastname: Liu
authors.forename: David
authors.initials: D
authors.lastname: Olivos
authors.forename: Mary
authors.initials: M
authors.lastname: Saunders
authors.forename: Kit S
authors.initials: KS
authors.lastname: Lam
authors.forename: Jan
authors.initials: J
authors.lastname: Nolta
authors.forename: Diana
authors.initials: D
authors.lastname: Olvera
authors.forename: Robert O
authors.initials: RO
authors.lastname: Ritchie
authors.forename: Nancy E
authors.initials: NE
authors.lastname: Lane
mesh_terms: D000375:Aging / Q000473:pathology; D019386:Alendronate / Q000494:pharmacology; D000818:Animals; D001862:Bone Resorption / Q000473:pathology / Q000628:therapy*; D001842:Bone and Bones / Q000187:drug effects / Q000378:metabolism / Q000473:pathology*; D002454:Cell Differentiation / Q000187:drug effects; D002465:Cell Movement / Q000187:drug effects; D004151:Dipeptides / Q000494:pharmacology; D004967:Estrogens / Q000172:deficiency; D005109:Extracellular Matrix / Q000187:drug effects / Q000378:metabolism; D005260:Female; D006801:Humans; D045164:Mesenchymal Stem Cell Transplantation; D059630:Mesenchymal Stem Cells / Q000166:cytology* / Q000187:drug effects / Q000201:enzymology; D051379:Mice; D008810:Mice, Inbred C57BL; D010006:Osteoblasts / Q000187:drug effects / Q000378:metabolism / Q000473:pathology; D010012:Osteogenesis / Q000187:drug effects; D010671:Phenylurea Compounds / Q000494:pharmacology; D010766:Phosphorylation / Q000187:drug effects; D019000:Phosphotyrosine / Q000378:metabolism; D051057:Proto-Oncogene Proteins c-akt / Q000378:metabolism
chemical_list: D004151:Dipeptides; D004967:Estrogens; C512274:LLP2A compound; D010671:Phenylurea Compounds; D019000:Phosphotyrosine; D051057:Proto-Oncogene Proteins c-akt; D019386:Alendronate
keywords: Bone marrow stromal cells; Cell migration; In vivo tracking; Integrins; Stem cell transplantation